1. Technical Field
The present invention generally relates to improved mobile telecommunications systems and in particular to improved packet-switched wireless/wired communication systems. Still more particularly, the present invention relates to an improved packet-switched telecommunications system which utilizes Internet Protocol packet communications.
2. Description of the Related Art
The written description utilizes a large number of acronyms to refer to components, methods and services. Although these acronyms, and the corresponding protocols and technologies, are known to those of skill in the art, for purposes of this discussion and convenience for the reader, acronyms will be defined as follows:
AMPS Advanced Mobile Phone Service. TIA analog cellular, and all standards that retain compatibility with it (NAMPS, D-AMPS, CDMA)
ANSI American National Standards Institute.
BSS Base Station System
DCCH Digital Control Channel. The control channel used by IS-136 and TIA/EIA-136 D-AMPS systems.
DTC Digital Traffic Channel
DMS Digital Multiplex Switch
EIA Electronics Industry Association
Gateway MSC An MSC designed to provide a gateway between a TIA/EIA-136/ANSI-41 network and a GPRS-136 network.
GGSN Gateway GPRS Support Node
GPRS Generalized Packet Radio Service. A GSM-based packet data protocol.
GSM Global System for Mobile Communications.
GTP GPRS Tunnelling Protocol
IMT International Mobile Telecommunications
ISUP ISDN User Part. SS7 signaling between switches.
MDIS Mobile Data Interface System
MGCP Media Gateway Control Protocol
MSC Mobile Switching Center
MSC-G Gateway MSC.
MSC-H Home MSC.
MSC-O Originating MSC.
MSC-V Visited MSC. The MSC in which a mobile is currently registered.
PDN Public Data Network
POTS Plain Old Telephone Service
PSTN Public Switched Telephone Network
Protocol A specification of the messages used to communicate over one or more interfaces.
RTP Real-Time Transport Protocol
SCP Signal Control Point
SGSN Serving GPRS Support Node
STP Signal Transfer Point
SS7 Signaling System Number 7
TDMA Time Division Multiple Access. A modulation technique used, e.g., by GSM.
TIA Telecommunications Industry Association TIA/EIA-136 TDMA air interface standard. Replaces IS-136.
XoIP Communications via Internet Protocol, where X can represent voice, data, video, etc.
In the current version of the ANSI TIA/EIA-136 and ANSI TIA/EIA-41 standards, the Digital Control CHannel (DCCH) and Digital Traffic Channel (DTC) support speech, asynchronous circuit-switched data, and G3 Fax services.
All three of these services are circuit-switched oriented. Revisions are now being made to the ANSI TIA/EIA-136 standard to produce ANSI TIA/EIA-136-A and ANSI TIA/EIA-136-B. ANSI TIA/EIA-136-A will specify a packet-switched data service known as xe2x80x9c136+xe2x80x9d or GPRS-136. ANSI TIA/EIA-136-B will specify a high-speed packet-switched service known as xe2x80x9c136HSxe2x80x9d or GPRS-136HS. The core technology for both of these packet-switched services is based on GPRS and EGPRS, respectively. These are ETSI GSM standards.
FIG. 1 shows a conventional GPRS-136-based network where voice and circuit-switched data is-still supported by the circuit switched network 103/104 but packet-switched data is supported by the GPRS-136 packet data network 106. Gateway MSC (G-MSC) 103 is a new functional entity standardized for GPRS-136, which is an MSC having the capability to provide a gateway to GPRS-136 network. Hence, G-MSC can be viewed as a part of MSC or a separate network Node. If it is considered a separate node, the SS7 xe2x80x98Exe2x80x99 interface is used to exchange signaling messages with MSC.
In FIG. 1, a mobile station MSx 101, which incorporates a vocoder and handles voice or circuit-switched data calls, communicates over the air with a BSSx switch 102, which supports voice and/or circuit switched data. The BSSx 102 communicates via both a T1 bearer traffic interface and a signaling interface A with a gateway mobile switching center 103. The SS7 network 104 is connected, in turn, with a terminating network 105 and a GPRS-136 network 106. Note that connection Gsxe2x80x2, between the SS7 network 104 and the GPRS-136 network 106, is a signaling interface only.
A GPRS-136 mobile station MSy 107, also incorporating a vocoder and configured to support voice and/or packet-switched data, communicates over the air with a BSSy switch 108, which supports packet data. The BSSy 108 communicates over a bearer traffic interface Gbxe2x80x2 with the GPRS-136 network 106. For voice calls, the vocoder of MSy 107 communicates with the BSSx switch 102, as described above.
GPRS-136 network 106 is connected to Public Data Network (PDN) 109. The PDN includes any destination terminal equipment 110.
TDMA service operators have expressed a desire to implement XoIP over the GPRS-136 network (where X can represent voice, data, video, etc., e.g., VoIP). XoIP can be implemented over the circuit-switched or packet-switched air interface. However, the current interface Gsxe2x80x2 to the GPRS-136 packet-switched network is standardized for signaling only and is implemented via SS7. Therefore, if the circuit-switched air interface is to be used, this is a problem, because XoIP involves the transmission of both signaling and bearer traffic. Therefore, the SS7 interface is inappropriate and an XoIP solution utilizing the GPRS-136 network would be greatly desired.
It is therefore one object of the present invention to provide an improved mobile telecommunications system.
It is another object of the present invention to provide an improved packet-switched mobile telecommunications system.
It is yet another object of the present invention to provide an improved packet-switched telecommunications system which utilizes Internet Protocol packet communications.
The foregoing objects are achieved as is now described. According to the preferred embodiment of the invention, the SS7 interface of a conventional GPRS-136 network is replaced with an IP interface. In this embodiment. an IP interface is placed in parallel with the Gsxe2x80x2 interface between the DMS MSC/G-MSC and the GPRS-136 packet-switched network. This interface can handle both signaling and bearer traffic and thereby overcomes the limitations imposed by the current SS7 interface, which can handle only signaling.
The above as well as additional objectives, features, and advantages of the present invention will become apparent in the following detailed written description.